WO2004069563A1

WO2004069563A1 - Non-pneumatic tire

Info

Publication number: WO2004069563A1
Application number: PCT/JP2004/001159
Authority: WO
Inventors: Yusaku Katoh; Hirotaka Ozaki
Original assignee: Fukuyama Gomu Kogyo Kabushiki Gaisha
Priority date: 2003-02-05
Filing date: 2004-02-04
Publication date: 2004-08-19
Also published as: JP4370599B2; CN1798662B; JPWO2004069563A1; CN1798662A

Abstract

If a non-pneumatic tire (1) with holes (6) that are opened in tire side faces has a crack in a hole-portion wall (9), tire replacement is necessitated even if the tire still maintains performance that it should have. This is because the external appearance of the tire degrades its value. However, such a problem is solved by preventing the occurrence of a crack in the hole-portion wall (9) without sacrificing cushioning characteristics, resistance to heat generation, and wear resistance that the non-pneumatic tire (1) with holes inherently has. The prevention is achieved by providing reinforcement rubber (8) having excellent stretch fatigue resistance at least at the outer side, in the radial direction of the tire, at the circumference of each hole (6) opened in the tire side faces.

Description

Specification

Non-pneumatic tires Technical field

TECHNICAL FIELD The present invention relates to a non-pneumatic tire having a large number of holes opening on the side of the tire. Technology background

Conventionally, pneumatic tires have been used for wheels for industrial vehicles such as forklifts and wheel loaders. However, punctures may occur on rough roads while carrying heavy loads. If punctures are likely to occur, non-pneumatic tires (solid tires) are often used instead of pneumatic tires. .

However, non-pneumatic tires have high rigidity, and the unevenness of the road surface is transmitted to the fuselage as vibration, resulting in poor ride comfort, and bad effects on the fuselage such as cracked wheels.

Therefore, a method has been proposed in which a hole is formed in the side surface of a non-pneumatic tire as a method of making use of the characteristics of a non-pneumatic tire that does not puncture and providing cushioning. The ideal form of holes for non-pneumatic tires with holes on this side is described in Japanese National Publication of International Patent Application No. Hei 11-151, Japanese Patent Publication No. 2001-2014 This is disclosed in Japanese Patent Application Laid-Open No. 5452/2002 and Japanese Patent Application Laid-Open No. H10-23632 / 17. Non-pneumatic tyres with holes that have been put into practical use based on those proposals have been put into the field and widely used. Figure 13 shows an example of a conventional non-pneumatic tire (solid tire) provided with holes that open on the side of the tire, that is, a perforated solid tire.

As shown in FIG. 13, the conventional perforated solid tire T is formed of a rubber elastic material, and has a base portion B of an inner peripheral portion to be mounted on a rim (not shown) and a tread on a tread side. D is arranged on a concentric circle, Are provided with a plurality of holes H in the tire axial direction.

Originally, the inner peripheral part of the non-pneumatic tire that fits with the rim is made of highly rigid rubber to firmly fix the tire to the rim. In addition, the middle part between the inner peripheral part that fits the rim of the non-pneumatic tire and the tread part that is grounded on the road surface has a cushioning property to prevent vibration transmission to the fuselage and consider riding comfort. Good rubber is used. In general, rubber with good wear resistance is used for the tread part in consideration of wear due to friction with the road surface, and the tread part and the middle part may be made of the same rubber. .

This configuration is the same for a non-pneumatic tire provided with a hole that opens on the tire side surface, that is, a perforated solid tire, and the hole that opens on the tire side surface is usually an intermediate portion or a cushioned portion. It is provided on a rubber layer that straddles the tread and the middle.

In such a non-pneumatic tire having a hole opened on the side surface of the tire, when the tire body on the ground contact side deforms by receiving a load, the shape of the hole located at that portion also changes. Therefore, when the vehicle runs and the tires rotate, each hole repeatedly deforms, and the most deformed portion of the wall surface of each hole repeatedly generates large strains.Although the frequency of occurrence is low, the tire tread wears out. Before the end of the tire life, the rubber in this area may gradually fatigue and crack. In this case, although the performance of the tire is maintained, the value of the tire is reduced in appearance, and the tire must be replaced, which is a problem. The crack generation phenomenon in the hole wall is often observed particularly in a portion where repeated elongational strain is generated, and is more likely to occur in a portion outside the hole in the tire radial direction because the deformation of the tire is larger as the tire is closer to the tire tread.

As a countermeasure, it is conceivable to design a hole shape so that the strain is not concentrated on a part when the tire is deformed. However, the driving conditions of the vehicle equipped with tires, that is, the hole deformation at the time of steady running, starting, and braking, etc. Everything is different. Therefore, the deformation state of the hole changes according to the situation, and the strain concentration area is not limited to a fixed place but moves, so that effective design is not easy. Further, as described above, the hole that opens to the tire side surface is formed in the cushion portion, which is the middle portion, or in the tread portion and the cushion portion. However, the rubber of the cushion where the holes are drilled is designed mainly for cushioning and heat resistance, and the rubber of the tread is designed for wear resistance. For this reason, fatigue resistance to repeated deformation is not considered, and when the tire rotates and the hole is repeatedly deformed, there is a risk that cracks will be generated from the strain concentration area of the hole wall, especially the part where extension strain occurs. There is.

In general, rubber has good rebound resilience, but has good cushioning and heat resistance, but has poor elongation fatigue resistance to repeated deformation, and poor rebound resilience rubber has good fatigue resistance to repeated deformation. However, there is a trade-off between cushioning and poor heat resistance.

Therefore, if the cushion rubber is designed in consideration of elongation fatigue resistance, cushioning performance and heat resistance will be sacrificed, and tires with poor cushion performance and heat resistance will not be used. Become. Similarly, if the tread rubber is designed in consideration of elongation fatigue resistance, wear resistance will be sacrificed, resulting in a tire with poor wear resistance and a short life.

The present invention is intended to provide a cushioning device having a cushioning property inherent to a conventional perforated non-pneumatic tire without sacrificing heat resistance and abrasion resistance. It is an object of the present invention to provide a non-pneumatic tire having an opening on the side surface of a tire in which a crack is not easily generated in the tire and a crack is not easily grown even if a crack is generated. Disclosure of the invention

The present invention has been made to achieve the above object, and the non-pneumatic tire of the present invention is formed of a rubber elastic material or the like, and has a large number of openings on the side surface of the tire. It is characterized by having a hole, and arranging a reinforcing rubber having better elongation fatigue resistance than the periphery of the hole, at least on the outer side in the tire radial direction around the hole.

In the above configuration, when the ground contact side portion of the tire is deformed by receiving a load, the hole opened on the side of the tire is also deformed, and when the tire rotates, the hole is repeatedly deformed and concentrated on a part of the hole outside in the tire radial direction. However, the reinforcement rubber, which is more resistant to elongation and fatigue than the periphery of the hole, is arranged at least around the periphery of the hole in the radial direction of the tire. It is possible to prevent or delay the generation of cracks in the hole wall on the radially outer side of the tire without impairing the characteristics of the portion, thereby prolonging the life of the tire.

Further, the present invention is characterized in that a reinforcing fabric, a reinforcing wire, or the like is embedded in at least a radially outer side of a large number of holes opened on the tire side surface of the non-pneumatic tire.

With the above structure, when the hole is deformed due to the rotation of the tire, when a load is applied to the hole wall outside the hole in the radial direction of the tire, the reinforcing material acts as a cushioning material to disperse the load and disperse the load. In order to prevent or reduce the occurrence of cracks, it is possible to prevent or delay the occurrence of cracks in the hole wall on the outer side in the tire radial direction without impairing the properties of the tread portion and cushion portion . Also, even if a crack is generated around the hole wall outside the hole in the tire radial direction, the growth of the crack can be prevented and delayed.

In addition, the present invention arranges a reinforcing rubber, which is more excellent in elongation fatigue resistance than the periphery of the holes, in at least the outer side in the tire radial direction of a large number of holes opened on the tire side surface of the non-pneumatic tire, and It is characterized by embedding a reinforcing cloth and a strong wire.

With the above configuration, in addition to the above-described effect of preventing the cracking of the reinforcing rubber, the effect of reducing the strain of the reinforcing material is added, and the occurrence of a strain concentration area outside the hole in the tire radial direction is reduced. Can be effectively prevented and alleviated, so that cracks are hardly generated, and a more excellent crack prevention effect can be obtained.

Incidentally, a reinforcing rubber arranged in the radially outer side at least around the hole opened to the tire side, the stretch fatigue test, the product of the depth and length of cracks generated reaches 1 0 0 mm ² The number of times is preferably 150,000 or more, more preferably 300,000 or more.

In addition, the reinforcing material of the present invention embedded at least in the tire radial direction around the hole opening on the side surface of the tire is formed of a wire composed of a synthetic fiber such as a nylon fiber or a polyester fiber. At this time, the reinforcing material formed on the fabric also has flexibility.

As described above, by using the reinforcing material, the load applied to the outer side of the hole in the tire radial direction can be effectively dispersed, and the generation of the strain concentration region can be prevented or reduced, and the generation of the crack can be suppressed. Even if a crack occurs, the growth of the crack can be prevented and delayed. In addition, the occurrence of trauma due to contact with obstacles can be reduced, and even if trauma occurs, the trauma is not easily transmitted and the enlargement of the wound can be prevented. BRIEF DESCRIPTION OF THE FIGURES

[Brief description of the drawings]

FIG. 1 is a cross-sectional view along a tire axis showing a first embodiment of a perforated solid tire of the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 shows another embodiment of the perforated solid tire of the first embodiment, where A is a cross-sectional view taken along the tire axis indicated by the left half of the tire of Another Example 1, and B is the tire of Another Example 2. FIG. 7C is a cross-sectional view taken along the tire axis indicated by the left half thereof, and C is a cross-sectional view taken along the tire axis indicated by the left half of the tire of another example 3.

FIG. 4 shows a second embodiment of the perforated solid tire according to the present invention. 1 is a cross-sectional view along the tire axis, and FIG. 1B is a cross-sectional view taken along line XX of A. FIG. 5 shows another example 1 of the perforated solid tire according to the second embodiment, in which A is a cross-sectional view along the tire axis showing the tire in the left half, and B is a cross-sectional view taken along line X-X of A. FIG.

FIG. 6 shows another example 2 of the perforated solid tire of the second embodiment, where A is a cross-sectional view along the tire axis showing the tire in the left half, and B is the X-X line of A. It is sectional drawing.

FIG. 7 shows another example 3 of the perforated solid tire according to the second embodiment, where A is a cross-sectional view along the tire axis showing the tire in the left half, and B is the X-X line of A. It is sectional drawing.

FIG. 8 shows another example 4 of the perforated solid tire of the second embodiment, in which A is a cross-sectional view along the tire axis showing the tire in the left half, and B is the X-X line of A. It is sectional drawing.

FIG. 9 shows a third embodiment of a perforated solid tire according to the present invention, in which A is a cross-sectional view along the tire axis showing the tire in the left half, and B is a cross-sectional view taken along line X-X of A. FIG.

FIG. 10 shows the situation and results of a strain test performed on a conventional non-pneumatic tire and another example 3 of the second embodiment of the present invention, where A is a conventional non-pneumatic tire with no load applied. B is a partial side view of the tire showing the condition of the non-pneumatic tire of another example 3 of the second embodiment where no load is applied, and C is a load of 2 tons. D is a partial side view of the tire showing the state of the conventional non-pneumatic tire when it is applied.D shows the state of the non-pneumatic tire of Alternative Example 3 of the second embodiment when a load of 2 tons is applied. E is a partial side view of the tire shown, and E is a table showing the amount of change and strain rate when a load is applied.

FIG. 11 is a diagram illustrating a rubber test piece for testing elongation fatigue resistance against repeated deformation.

FIG. 12 shows a specific compounding example of the reinforcing rubber of the present invention, its characteristics, and the conventional rubber. The following table shows examples of general blending of rubber for the tread portion and rubber for the cushion portion and a table comparing the characteristics thereof.

FIG. 13 is a partially broken perspective view showing an example of a conventional perforated solid tire.

Explanation of reference numerals

1 is a perforated solid tire, 2 is a base, 3 is a tread, 4 is a cushion, 5 is a tire side, 6, 6a and 6b are holes, 7, 7a and 7a are Openings, 8, 8a, 8b are strong rubber, 9 is a hole wall, 10 is a reinforcing material, 11 is a metal plate, 12 is a rubber test piece, h is the rubber height of the test piece, D is the rubber diameter of the test piece, and S is the bead wire. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 and 2 show a first embodiment of a perforated solid tire 1 of the present invention. FIG. 1 is a sectional view taken along the tire axis, and FIG. 2 is a sectional view taken along line X--X in FIG. is there.

In the first embodiment, a non-pneumatic perforated solid tire 1 is formed of an elastic material such as rubber, and has a base portion of an inner peripheral portion mounted on a rim.

2 and the tread portion 3 on the ground plane side are arranged concentrically. Further, a cushion portion 4 is formed between the two portions, and a plurality of holes 6a, 6b are formed in the left and right side surfaces 5a, 5b of the tire in the axial direction of the tire, respectively. It is arranged in the direction. The reinforcing rubbers 8a, 8b are disposed so as to cover the tire side surfaces 5a, 5b in a range including the openings 7a, 7b of the holes 6a, 6b.

The range in which the reinforcing rubbers 8a and 8b cover both side surfaces 5a and 5b of the tire is a range including at least the openings 7a and 7b of the holes 6a and 6b, and only the side surfaces of the cushion portion. Configuration, cushion and tread, or It is also possible to arrange it so as to straddle the sillon part, the tread part and the base part. In addition, the reinforcing rubbers 8a and 813 extend from the openings 7a and 7b of the holes 6 & and 6b in the hole depth direction, and extend from about one quarter of the hole depth to the entire hole. It is configured to cover.

As a specific example, in the case of a tire of 7.0-0-12, the thickness of the reinforcing rubbers 8a and 8b arranged on both side surfaces 5a and 5b of the tire is 5 to 15 mm, and the holes 6a and The reinforcing rubbers 8a and 8b covering the periphery of 6b in the hole depth direction gradually decrease in the depth direction to reach about one third to two thirds of the hole depth.

The rubber material used for the reinforcing rubbers 8a and 8b is a rubber having good elongation fatigue resistance. For example, the hardness {JIS K6253 (1997) durometer A hardness} is 50 to 80 degrees, and natural rubber is used. And polybutadiene rubber as the main component, and a nitrogen-adsorbing specific surface area of 70 to 1 as a reinforcing agent

Carbon blacks of the ISAF and HAF classes are appropriately mixed and used, and those using an appropriate combination of siri forces are also suitable. Fig. 12 shows specific examples of blending of preferred reinforcing rubbers and their properties (Blending Examples 1 to 3), and conventional examples of blending of tread rubber and torsion rubber and their properties. Shown in

The elongation fatigue resistance test shown in the table of Fig. 12 is a cylindrical shape with a height h of 18 mm and a diameter D of 21 mm with both ends bonded to a metal plate 11 as shown in Fig. 11 The rubber test piece 12 was repeatedly stretched 25% in the height direction at a frequency of 300 times a minute.

Then, the number of times until the product of the depth and the length of the crack generated in the test piece reached 100 mm ² was measured.

In the table, the reinforcing rubber, tread de section rubber and number to withstand elongation fatigue resistance click Ssho down the rubber, i.e., the product of the depth and length of a crack generated in the test piece reaches 1 0 0 mm ^2, is In Examples 1-3 of the compounding of the reinforcing rubber, the number of rubbers was 310,000, 3,570,000, and 300,000, respectively, whereas the rubber of the tread was 107,000, and the rubber of the cushion was 100,000. 4 30,000 times, Example of reinforcing rubber compounding 1 ~ The elongation fatigue resistance of No. 3 is about three times that of the rubber at the tread and about seven times that of the rubber at the cushion.

The service limit of normal non-pneumatic tires (solid tires) depends on the wear of the tread, and the life of the tread will be reached. However, in the case of perforated non-pneumatic tires, cracks occur due to deformation strain in the hole wall before the tire life due to abrasion of the tire tread, and the performance as a tire is maintained. Nevertheless, you may have to change tires.

For this reason, it is desirable to prevent the occurrence of cracks due to deformation strain applied to the hole wall, and to limit the service life due to abrasion of the tire tread to the limit of the use of perforated non-pneumatic tires, as with ordinary non-pneumatic tires. It is.

To achieve this purpose, as described above, prevent cracking of the hole wall without impairing the cushioning property of non-pneumatic tires, heat resistance (cushion part), and wear resistance (tread part). Therefore, reinforcing rubber was placed around the hole. As the reinforcing rubber, a rubber having more elongation fatigue resistance than the cushion rubber and the tread rubber as in the compounding examples 1 to 3 shown in the table of FIG. 12 is used. The perforated non-pneumatic tire 1 having such a configuration has an extension fatigue resistance against repeated deformation around the openings 7a and 7b of the holes 6a and 6b on the tire side surfaces 5a and 5b. Since the reinforcing rubbers 8a and 8b with good performance are arranged, even if the holes 6a and 6b are deformed repeatedly, the elongation strain is repeatedly generated on the radially outer side of the hole wall 9 where the elongation strain is large. In other words, cracks can be prevented without impairing the properties of the tread and cushion, and even if cracks occur, their growth can be delayed, and the life of perforated non-pneumatic tires can be extended. it can.

Furthermore, since the strength of the tire side surfaces 5a and 5b including the openings 7a and 7b of the holes 6a and 6b is improved, even if the tire collides with an obstacle or the like, the occurrence of trauma can be reduced. The growth of cracks from the wound can also be delayed. FIG. 3 shows other examples 1 to 3 of the perforated solid tire of the first embodiment.

Another example 1 shown in FIG. 3A has a configuration in which the reinforcing rubber 8 covers the tire side surface 5 including the tire radially outside around the hole 6.

Another example 2 shown in FIG. 3B has a configuration in which the thickness of the reinforcing rubber 8 covering the tire side surface 5 is increased and the reinforcing rubber 8 covers the entire hole 6.

Another example 3 shown in FIG. 3C has a configuration in which the thickness of the reinforcing rubber 8 covering the tire side surface 5 is reduced and only the tire side surface around the hole 6 is covered.

FIG. 4 shows a second embodiment of the perforated solid tire of the present invention.

The basic configuration of the second embodiment is as follows. Instead of the reinforcing rubber of the first embodiment, the reinforcing members 1.0a and 10b are provided in the range including the openings 7a and 7b of the holes 6a and 6b. The tire is embedded along the tire side surfaces 5a and 5b in the circumferential direction of the tire, and embeds the rubber of the cushion portion 4 or the rubber of the tread portion 3 and the base portion 2 around the holes 6a and 6b. The configuration is covered.

The reinforcing members 10a and 10b are formed of a woven fabric made of synthetic fibers such as nylon and polyester fibers, and may be made of a material having elasticity in each direction.

Further, an adhesive treatment may be performed on the tire body, and whether or not the adhesive treatment is performed is not particularly limited.

With this configuration, when the tire rotates and the holes 6a and 6b are repeatedly deformed, the load applied to the outer side of the hole wall 9 in the tire radial direction is dispersed by the reinforcing members 10a and 10b, and the elongation strain is increased. This can prevent or mitigate the formation of concentrated areas, and can prevent the occurrence of cracks. Further, even if a crack occurs, the growth of the crack can be prevented or delayed.

In addition, since the reinforcing materials 10a and 10b are buried in both sides 5a and 5b of the tire including the openings 7a and 7b of the holes 6a and 6b, contact with obstacles The occurrence of trauma can be reduced, and even if trauma occurs, the trauma does not easily propagate and the enlargement of the wound can be prevented. 5 to 8 show other examples 1 to 4 of the perforated solid tire of the second embodiment. Another example 1 shown in FIG. 5 has a configuration in which the reinforcing material 10 is continuous along the tire circumferential direction and embedded along the tire radial outside of the hole 6 and the tire side surface 5 including the tire radial outside of the hole 6. I have.

Another example 2 shown in FIG. 6 has a configuration in which the reinforcing material 10 is buried so as to be continuous in a belt shape in the tire circumferential direction so as to cover the outside of the hole 6 in the tire radial direction.

Another example 3 shown in FIG. 7 has a configuration in which a plurality of reinforcing members 10 formed of a wire made of a steel cord are embedded around the hole 6.

Another example 4 shown in FIG. 8 has a configuration in which a cap-like reinforcing material 10 is embedded around the entire periphery of the hole 6.

FIG. 9 shows a third embodiment of a perforated solid tire according to the present invention. The third embodiment has a configuration in which another example 1 of the first embodiment and another example 1 of the second embodiment are combined. The third example is located outside the hole 6 in the tire radial direction, and A reinforcing material 10 is embedded in a reinforcing rubber 8 arranged continuously in the tire circumferential direction.

With this configuration, it is possible to prevent the reinforcing material 10 from dispersing the load applied to the hole wall 9 and form a strain concentration area, and to prevent the reinforcing rubber 8 from cracking even if the strain concentration area occurs. Can be prevented.

Fig. 10 shows the results of a strain test performed on a conventional non-pneumatic tire and another example 3 of the second embodiment of the present invention and the results thereof. B is a partial side view of the tire showing the state of the non-pneumatic tire showing the state of the non-pneumatic tire, and B is a partial side view showing the state of the non-pneumatic tire of another example 3 of the second embodiment where no load is applied. Partial side view of the tire showing a state of the conventional non-pneumatic tire when a load of 2 tons is applied.D is a non-pneumatic tire of another example 3 of the second embodiment when a load of 2 tons is applied. And E is a table showing the amount of change and strain rate when a load is applied.

As shown in the test situation and table in Fig. 10, a reinforced material is buried around the hole. The resulting non-pneumatic tire has a strain rate at the end of the hole that is less than half that of a conventional non-pneumatic tire in which no reinforcing material is embedded. With a structure in which a reinforcing material is embedded around the hole, the stress-carrying material disperses the load applied to the hole when the tire is deformed by receiving a load, appropriately reducing the strain around the hole and reducing the concentration of strain. By preventing the crack, the occurrence of cracks is prevented, and the durability of the tire can be improved.

In the present invention, the reinforcing rubber, the reinforcing material, and the combination thereof are not limited to the above-described embodiment, and may be each combination of the above-described embodiments, or may be limited to these combinations. Absent.

Furthermore, the form of the hole opened on the tire side surface in each example is not limited to the shape of the hole shown in each example described above. For example, the shape of the hole is not limited to a circle, but may be elliptical, oval, It may be square, polygonal, or a combination thereof. Further, the number of holes arranged in a row in the circumferential direction may be a single layer or two or more layers, and the holes may penetrate in the tire axial direction or may be closed inside the tire. The arrangement of the holes may be arranged in parallel or alternately in a zigzag pattern in the right and left directions in the tire width direction and the upper and lower directions in the tire radial direction. Industrial applicability

Since the present invention is configured as described above, in a non-pneumatic tire having a hole that opens on the side surface of a tire, even if the hole is repeatedly deformed, it is possible to prevent or delay cracks generated in the hole, and Even if cracks occur, growth can be delayed.

Claims

The scope of the claims

1. In a non-pneumatic tire having a large number of holes opening on the tire side surface, a reinforcing rubber having better elongation fatigue resistance than the rubber around the holes is arranged at least around the holes in the tire radial direction outside. A non-pneumatic tire, characterized in that:

2. A non-pneumatic tire having a large number of holes opened on the side surface of a tire, wherein a reinforcing cloth, a reinforcing wire, or the like is embedded at least around the hole in the radial direction of the tire.

3. In a non-pneumatic tire having a large number of holes that open on the side of the tire, a reinforcing rubber with better elongation fatigue resistance than the rubber around the holes is arranged at least around the holes in the radial direction of the tire. A non-pneumatic tire characterized by embedding a reinforcing cloth and a reinforcing wire.